After he graduated in 1887 Park's concern for social issues, especially issues related to race in cities, led him to become a journalist. Franklin Ford and Park planned a newspaper, titled Thought News, which would register public opinion like business papers recorded changes in the stock market . The news paper was never published, but Park still pursued a career as a journalist. From 1887 through 1898 Park worked as a journalist in Detroit, Denver, New York, Chicago, and Minneapolis.[2] This encounter with journalism influenced his later work in sociology.

After working as a journalist in various U.S. towns from 1887–1898 he studied psychology and philosophy while studying with another prominent pragmatistphilosopher, William James. Park earned a MA at Harvard in 1899. After graduating, he went to Germany to study at Freiderich Wilhelm University. He studied philosophy and sociology in 1899–1900 with Georg Simmel in Berlin, spent a semester in Straßburg (1900), and took his PhD in Philosophy in 1903 at Heidelberg under Wilhelm Windelband (1848–1915) and Alfred Hettner (1859–1941) with a dissertation titled Masse und Publikum. Eine methodologische und soziologische Untersuchung (Crowd and Public: A methodological and sociological study). He returned to the United States in 1903, briefly becoming an assistant professor in philosophy at Harvard 1904-5[3]

Park taught at Harvard, until Booker T. Washington invited him to the Tuskegee Institute to work on racial issues in the southern U.S. Park was a publicist for the Tuskegee Institute and later became a director of public relations. Over the next seven years, Park worked for Washington doing field research and taking courses. In 1910, Park traveled to Europe to compare U.S. poverty to European poverty. Shortly after the trip, Washington, with the help of Park, published The Man Farthest Down (1913).[3]

After Tuskegee, Park joined the Department of Sociology at the University of Chicago in 1914, first as a lecturer (1914–1923) then as a full professor of sociology until his retirement in 1933.[2] During his time at the University of Chicago, he continued to study and teach human ecology and race relations. After leaving the University of Chicago, Park moved to Nashville, Tennessee. He taught at Fisk University until his death in 1944, at age 79.[2]

During Park's time at the University of Chicago, its sociology department began to use the city that surrounded it as a sort of research laboratory. His work – together with that of his Chicago colleagues, such as Ernest Burgess, Homer Hoyt, and Louis Wirth – developed into an approach to urban sociology that became known as the Chicago School[2]

“My contribution to sociology, has been, therefore, not what I intended, not what my original interest would have indicated, but what I needed to make a systematic exploration of the social work in which I found myself. The problem I was interested in was always theoretic rather than practical. I have been mainly an explorer in three fields: Collective Behavior; Human Ecology; and Race Relations.[2]

Urban Ecology[edit]

Park created the term human ecology, which borrowed concepts from symbiosis, invasion, succession, dominance, gradient growth, super ordination, and subordination from the science of natural ecology.[4] Bogardus has estimated that it is rather well recognized that Park was the father of human ecology, "Not only did he coin the name but he laid out the patterns, offered the earliest exhibit of ecological concepts, defined the major ecological processes and stimulated more advanced students to cultivate the fields of research in ecology than most other sociologists combined.[5]

While at the University of Chicago, Park continued to strengthen his theory of human ecology and along with Ernest W. Burgess developed a program of urban research in the sociology department.[3] They also developed a theory of urban ecology, which first appeared in their book Introduction to the Science of Sociology (1922). Using the city of Chicago as an example, they proposed that cities were environments like those found in nature. Park and Burgess suggested that cities were governed by many of the same forces of Darwinian evolution that happens in ecosystems. They felt the most significant force was competition. Competition was created by groups fighting for urban resources, like land, which led to a division of urban space into ecological niches. Within these niches people shared similar social characteristics because they were subject to the same ecological pressure.[6]

Competition for land and resources within cities eventually leads to separation of urban space into zones with the more desirable zones imposing higher rent. As residents of a city become more affluent they move outward from the city center. Park and Burgess refer to this a succession, a term also used in plant ecology. They predicted that cities would form into five concentric rings with areas of social and physical deterioration concentrated in the center and prosperous areas near the city’s edge. This model is known as concentric zone theory, it was first published in The City (1925).[6]

Race Relations[edit]

Robert E. Park spent a great deal of time studying race relations with Booker T. Washington and while and the University of Chicago.[1] E.C. Hughes said that, “Park probably contributed more ideas for analysis of racial relations and cultural contracts than any other modern social scientist.[5] "

Park worked closely with Booker T. Washington and the Tuskegee Institute from 1907 to 1914. While working under Washington, Park’s primary interest was the system that had evolved to define Black-White relations in the South. Park said that he learned more about human nature and society while in the South. He says that, “These seven years were for me a sort of prolonged internship during which I gained a clinical and first hand knowledge of a first class social problem . . .[It was from Washington that] I gained some adequate notion of how deep-rooted in human history and human nature social institutions were, and how difficult, if not impossible it was, to make fundamental changes in them by mere legislation or by legal artifice of any sort."

After leaving the Tuskegee Institute, Park joined the University of Chicago where he developed a theory of assimilation, as it pertained to immigrants in the United States, known as the “race relation cycle”. The cycle has four stages: contact, conflict, accommodation, and assimilation. The first step is contact followed by competition. Then, after some time, a hierarchical arrangement can prevail – one of accommodation – in which one race was dominant and others dominated. In the end assimilation occurred. Park declared that it is “a cycle of events which tends everywhere to repeat itself” and that it can also be seen in other social processes.[7] "